1. Field of the Invention
The present invention is related to an X-ray detector and a fabrication method of X-ray detector, and more particularly, to an X-ray detector by utilizing a silicon-rich (Si-rich) dielectric layer as photo-sensing material and a fabrication method thereof.
2. Description of the Prior Art
In contrast to the traditional negative-type X-ray detector system, a digital X-ray flat indirect detector system has advantages of low irradiation and fast imaging of electric images. In addition, the images of digital X-ray flat indirect detector system is easily to be viewed, reformed, extracted, transferred, and analyzed. Therefore, the digital X-ray flat indirect detector system has been a mainstream in current medical digital image technology. A digital X-ray flat indirect detector system includes a sensing pixel array, and each sensing pixel includes a thin film transistor (TFT), a photo-sensing device and a luminous material that transforms X-ray into visible light. Generally, the photo-sensing devices of a traditional digital X-ray flat indirect detector system are mainly formed with P-type/intrinsic/N-type (PIN) photodiodes that are composed of amorphous silicon materials. However, a PIN photodiode has a very large thickness, which is about 1-2 micrometers (μm), and is conductive itself. Therefore, many isolation layers have to be formed around the PIN photodiode in order to avoid short defect occurring between the PIN photodiode and adjacent devices, such as sensing electrodes. As a result, the fabrication process that integrates the PIN photodiodes and the sensing pixel array having devices such as TFTs usually includes 12 to 13 steps of thin-film deposition processes and photolithography-etching processes, which spends a lot of time and costs much money. Accordingly, it is still an important issue for manufacturers of X-ray detector system to keep on researching in order to design new structure or new photo-sensing materials that can effectively replace PIN photodiodes for fabricating digital X-ray flat indirect detector system through simple processes.